Troxels new Liberty features a ultra low profile design with dial fit technology and a classic high gloss finish created for schooling and all-purpose riding. New animal print headliners! New Matte Duratec colors! Now with GPS Dial Fit! Mesh Covered Vents Low profile Meets ASTM F-1163-04 standards Sizes - Small (up to 7 hat size or up to 22in; circumference); Medium (7 to 7 1/4 hat size or 22in; to 22 3/4in circumference; Large (7 1/4in and up hat size or 22 3/4in and up circumference). Please note that each persons head shape and size are unique, you may need to size up or down based on your unique shape. Please see chart for additional assistance in sizing.